The disclosed embodiments of the present invention relate to a protection mechanism for a touch panel device, and more particularly, to a protection circuit for detecting occurrence of noise interference that affects touch event detection of a touch panel device and enabling a protection mechanism for protecting the touch panel device from the noise interference when occurrence of the noise interference is detected, and related protection method and electronic device thereof.
Touch panel devices are now widely used in a variety of applications to act as user interfaces. In general, a touch panel device may include a touch panel and a touch controller. Regarding certain applications, capacitive touch panels (e.g., mutual-capacitance touch panels or self-capacitance touch panels) may be used. Thus, the touch controller generates a driving signal to the capacitive touch panel, receives a sensing output generated from the capacitive touch panel, and generates a touch event detection result (e.g., coordinate and/or action information of the detected touch event) according to the received sensing output.
However, under certain conditions, the touch panel device may not work as expected. For example, when there is undesired noise interference, the touch event detection of the touch panel device may produce an erroneous output. For example, considering a case where the touch panel device is disposed in a mobile phone, the radio-frequency (RF) signals generated from and received by the mobile phone may also be coupled to the touch panel. When there is an RF signal with large amplitude, the noise interference introduced by such an RF signal would result in signal saturation. Consequently, the touch controller generates an erroneous touch event detection output due to the RF signal with large amplitude. Besides, when the user uses a low-cost/low-quality charger to charge a battery device of the mobile phone, the low-cost/low-quality charger may introduce high common-mode noise in the power supplied to the touch panel device, thus making the touch controller operate abnormally.
Thus, there is a need for a protection mechanism which is capable of protecting the touch panel device from undesired noise interference to thereby improve accuracy of the touch event detection.